I had some Bohemian malt left over and thought that this would be the perfect occasion for using up the remaining Saaz hops! The ingredients are very simple (as they should be)

  1. Bohemian Malt (85%)
  2. Munich Malt (15%)
  3. Northern Brewer (bittering)
  4. Saaz (Flavour and Aroma)
  5. Budvar Yeast
  6. Water

I don’t know whether it’s my taste-buds or whether the brewery in Budvar recently changed the way they do their original Budweiser, but to me it seems to have lost it’s delicate malt flavour and nowadays it tastes way too thin and without enough substance.  So I’m aiming to underline the malt character and this naturally calls for an approach using decoctions.  Now a quick look at the malt specifications

Malt Dry Extract (%) Colour (EBC) Moisture (%) Kolbach Index (%)
Bohemian Malt 79 4 5.5 38
Munich Malt 80 11.9 3.1 40.6

Note that UK malt specs are reported differently than is the custom in Germany.   I used the Extract LDK (dm) value for the dry extract and divided the number by 386 to get the percentage in decimal.  Also, the Kolbach Index is expressed differently but given as SNR – which is the Soluble Nitrogen Ratio and effectively the same.  If that isn’t given either, then you can work it out by dividing the Soluble Nitrogen % by the Total Nitrogen % (and if that’s not on your spec sheet either, change maltster). Now a quick look at the table from Hanghofer and I decide to go for a 20 minute protein rest at 54C since the main malt is less modified. Traditionally this would call for a triple decoction mash, but this would involve a protein rest that is too long.  Enter the double decoction mash!

Bavarian Hochkurz Deoction Schedule
Bavarian Hochkurz Deoction Schedule

This type of schedule is also known as Hochkurz and is often used in Bavarian breweries when the malts’ modifications is higher.   If the Bohemian malt would have been a bit more modified then the schedule could have started at 62C.  Since a short protein rest is necessary it starts at 54C (well, it was borderline… I might try one later without and see what difference it makes). What the graph doesn’t show is the amount of water needed.  Loads!  For computer-brewers this might come of as a shock, but I never bother to work out the amount of sparge water needed.  Never.   This is because I stop the sparge at 5 or 6 Brix in order to avoid extracting tannins and other unwanted material.  In a dark and heavily hopped beer this may not show,  but in a subtle Pale Ale or Lager any brew faults like this will be very noticeable. A three vessel setup is necessary

  1. HLT – for heating up water for the infusions
  2. Brew Kettle –  for heating up the decoction mash
  3. Mash Tun – for keeping the grains and sparging (Firefox auto-corrected this to spanking FYI)

This is not too dissimilar from what most english home-brewers have, except for the brew kettle to heat the mash.   This can be done with household implements though.  Any 12l pot would do nicely.  It can be done on a stove.  In fact, I’ve done it on a stove for quite a while until I decided to upgrade (and downgrade the complaints from my girlfriend). Let’s start

0:00:00 Mash-In at 54C

image The grain is milled and the mixture is added to the brew kettle.  Then water is infused to raise the temperature to 54C and a water to grist ratio of 1:2.  This is quite a thick mash and proteases work well under these conditions.

00:20:00 Infusion to 62C

image Before the next step is taken, a pH reading is obtained and the mash is corrected with Acidulated Malt to bring the pH to 5.3 – 5.4.  Even though some pH meters have Automatic Temperature Compensation (ATC), the mash needs to be cooled to 20C for a correct reading.  I noticed that my pH meter needs a correction of 0.2 even though it has ATC. I added 3g CaCl2, 1.3g CaSO4, 1.7g sea salt and adjusted the mash pH to 5.35 The next infusion raises the temperature to 62C and brings the water to grain ratio to 3.6.

00:50:00 Dickmaische Ziehen!

image Dickmaische Ziehen is German for pulling a thick mash.   Because I started in the Sudpfanne, all I need to do is to run the resulting mash into the Sparge Tun.  My valve is 22cm and at this stage the mash is thin enough to do this without problems. This is a bit different than most books will tell you.  Scooping is messy and labour intensive.  Doing it the other way round works just as well and is faster.

Sudpfanne after most of the thin mash has  run off
Sudpfanne after most of the thin mash has run off

4l of water at 72C are added to the remaining mash in the brew kettle.   This serves several purposes

  1. it prevents excessive caramelisation and scorching of the grains
  2. allows my mash agitator to work better
  3. helps the decoction to achieve it’s first rest temperature quicker
  4. better extraction of remaining starches
  5. higher remaining enzymes in the sparge tun for conversion
  6. it confuses Americans

The agitator is switched on and the contents are heated to 72C.  In the meantime the water is heated to 87C in the HLT.

01:10:00 Added 10l of water at 87C to the Dickmaische and raise temp to 95C

To obtain a bright wort without excessive melanoids and tannins the mash is further thinned before it spends 10 minutes at 95C to extract more starches.  A lot of texts don’t make this clear enough.  The starches set free this way can still be converted once the decoction is returned to the sparge tun.   This provides plenty of food for the alpha-amylase to make dextrine, despite the long rest at 62C of the remainder in the mash tun. image

01:20:00 Aufmischen!   Main Mash raised to 72C

Aufmaischen is the German word for returning the decoction to the main mash (i.e. to the mash tun).  Again, because the decoction is quite thin it runs quite comfortably into the mash tun.   This happens in intervals and under a lot of stirring.  Great care must be taken not to scorch excessive amounts of the remaining enzymes.  In this particular case the target temperature of 72C was reached as 90% of the decoction had returned.  I really don’t care much about the thermal properties of the sparge tun in this case.  Anything that can be converted has already done so during this long pause.  The temperature at strike time may well be under 62C.  Again, I would not work out the exact amount to decoct etc… like some computer-brewers do.  I like the fact that I have a bit of leeway and adjust for seasonal temperature drops.  After a short period of cooling the remaining 10% are returned to the mash tun and the lid closed so that the alpha-amylase can perform it’s work on the newly extracted starches.

1:24:00 10l Läutermaische Ziehen!

This is my favourite bit.  Just like a sparge, the liquid is now run through the filter maze for the last decoction.   At this stage all the enzymes have done most of their work and it’s time to lock in the composition of the wort.

Pulling the last "Läuter" (thin) Decoction
Pulling the last “Läuter” (thin) Decoction

One nice advantage of boiling the thin mash is that it already forms a bit of hot-break, which can then be filtered through the grain bed thus resulting in a clearer wort hitting the boil kettle.

1:54:00 Boil 2nd Decoction for 10 minutes and Aufmaischen to 78C

After the Läutermaische has boiled for 10 minutes (one could easily prolong this to 20 minutes for a different flavour profile), it is returned to the mash tun in order to bring the remainder to 78C.  Again, having a bit of extra left in the brew kettle doesn’t hurt and is a good insurance against not hitting the desired target temperature.

2:08:00 Rest 15 minutes for Mash-Out

The graph above shows a shorter rest of 5 minutes.  I decided to prolong it to 15 minutes because I’ve always done it like this.  Not sure what possessed me to enter 5 minutes when I did the graph…

No need for a "Vohrlauf".  It's already clear enough thanks to the "Läuter" Decoction and the ample time the grain bed had to settle....
No need for a “Vohrlauf”. It’s already clear enough thanks to the “Läuter” Decoction and the ample time the grain bed had to settle….

Arguably, I could have waited a bit longer but to me the wort was clear enough to begin the sparge.  There is a huge volume of water in the mash tun by now, and it feels like a no-sparge brew.  Well, not quite.  It took just a few batches of 3l each to bring the runoff to a density of 6 Brix after which I stopped the sparge and topped up the remainder in the kettle to bring to the desired volume.   Tannins are the lager brewers’ worst enemy and I am happy to sacrifice a few percent efficiency but leaving the nasty stuff in the mash tun.

3:04:00  Boiling the Hops

Now the wort is boiled for 135 minutes.   I’ve got a new setup which gives me a bit more head space and a larger surface area for getting rid of DMS and other unwanted flavours. When correcting the water I always use 2/3 of the salts in the mash, the other 1/3 in the wort at boil-time.  Don’t know where I picked it up but “I learned it this way”. At this stage I perform the last 1/3 of the water treatment. 1g CaCl2, 0.7g CaSO4, 0.7g sea salt are added.  Feel free to comment. I still need to get to grips with Manchester water… image A 50l stainless steel pot from a good gastronomic supply (make sure it’s induction ready) and a 3500W commercial hob do the job nicely. image As the hot trub is solid enough it’s skimmed off so that it doesn’t end up in the fermenter. image

4:04:00 “Green Gold”

A very simple hopping schedule which starts for the remaining 60 minutes of the boil only. I didn’t know the evaporation rate of the new kettle (yes, I could have done the experiment but I don’t mind adjusting on the fly).  My previous kettle did 11.4% — which was a bit too high for my liking.  This one worked out at 10.4% — which is also pretty decent and I prefer the slightly gentler rolling boil.   I somehow felt that a too vigorous boil removed too much of the aroma too quickly.  But then again, this could be purely psychosomatic…

  • 5:04:00 5g of Northern Brewer
  • 5:24:00 30g Saaz
  • 5:44:00 30g Saaz
  • 5:54:00 30g Saaz

 5:24:00 Prepare the Heat Exchanger and Inline Aeration Stone

Preparing the heat-exchanger and the in-line aeration stone
Preparing the heat-exchanger and the in-line aeration stone

Not much to say about this, but I want to have it ready once the boil is done.  It’s no good being in a rush, especially with hot liquids, CO2 and O2 tanks about.  I don’t drink during the mash either.  Drinking whilst brewing is a very bad idea, especially when doing a decoction mash.

5:54:00 Let wort cool down to 80C – No Whirlpool

Since I’m using leaf hops and not pellets or crushed material, a whirlpool is not necessary. The hot trub is already skimmed and I am just letting the hops sink and settle.  It took about 10 minutes for the temperature to sink to 80C at which stage the hot liquid was pumped through the HE and O2 stone directly into the cyclonical fermenter.
At the end of the hose a in-line water meter provides for a useful read-out for how much wort actually ended up in the fermenter. image Still a bit of haze from the cold trub, but I like it for it’s fermentation enhancing properties.  My text-book from Weihenstephan claims that cold-trub gives a beer more flavour and it should only be filtered out if unwanted or off-flavours occur.  Considering the nature of the grain bill, I would say that performing a decoction schedule like this will not darken the wort in a noticeable manner.  Very happy with the results so far. The original gravity came to 13 degrees Plato (or just 13%), bang on.  Which is very Czech actually.  One often sees the beer there labelled by their original strength,  11, 12, 13, 16 etc.. Vielen Dank Herr Dreher!!!

7:02:00 Pitch Yeast at 6C

I prefer to ferment lagers at 8C (which is known as the cold fermentation schedule for bottom fermenting yeasts).  At the end of fermentation the final temperature will be 5C which is the perfect temperature for transferring the beer into the lager vessels… (more about this some other time).

6:30:02 The End

Time for a well deserved beer!   Prost!